Posted by Jay Bertolet on August 25, 1999 at 09:36:08:
In Reply to: Adding a fifth valve posted by Scott on August 24, 1999 at 22:58:19:
Adding a 5th valve to a tuba is, in my opinion, a fairly common procedure and certainly possible in almost all cases. Generally, if the horn is a rotary valve tuba, the 5th will be added to the top of the "stack" of valves, right before the 1st valve. If the horn is a piston valve tuba, the 5th is added after the stack, just past the main tuning slide. The latter is more tricky because the expansion of the pipe at that point can be extreme which means you have to find a valve with an extremely large bore. Also, building the linkage to such a valve can also be a little tricky but it can be done.
I have added 5th valves to two of my instruments, both rotary valve Cervany's, and both times the results were completely positive. I suffered no intonation problems on either instrument and the costs totaled around $500.00 each. If you're considering such an operation with your tubas, the advice I would offer is to take your time and plan the whole thing out. I ordered original factory parts for my tubas so that meant waiting quite some time for parts to arrive from Europe. I also ordered extra parts, specifically leadpipes, so that if there were any problems I could reverse the procedure and seek other alternatives. It also helps to have a top notch repair technician doing the work and helping you plan, someone who not only does repairs but is able to fabricate parts from scratch. That is how my linkages were done and it saves alot on money! A good technician will be able to help you assemble a complete list of the parts necessary to do the job right and help you make decisions about how you want the valve to function.
I swear by my 5th valves so the procedure was really invaluable to me. Good luck!